The present invention relates to oral controlled release dosage formulations containing an analgesic. More specifically, the present invention relates to an oral dosage formulation in the form of a tablet or a capsule containing pellets comprising a nonsteroidal anti-inflammatory drug (NSAID), preferably a propionic acid derivative such as ibuprofen, naproxen, flubiprofen, indoprofen, ketoprofen or there pharmaceutically acceptable derivatives. Most preferably the NSAID is ketoprofen.
Numerous techniques are in the prior art for preparing sustained or controlled release pharmaceutical formulations. One common technique involves surrounding an osmotically active drug core with a semipermeable membrane. The drug is released from the core over time by allowing a fluid such as gastric or intestinal fluid to permeate the coating membrane and dissolve the drug so the dissolved drug can permeate the membrane. In some cases a hydrogel is employed to push the active ingredient through the passageway in the membrane. Some representative examples of these osmotic tablet systems can be found in U.S. Pat. Nos. 3,845,770, 3,916,899, 3,952,741, 4,034,758, 4,077,407 and 4,783,337.
Another common technique for preparing controlled release pharmaceutical formulations is to encapsulate a plurality of beads, pellets or tablets that are coated with varying levels of a diffusion barrier and/or different types of the diffusion barriers. Examples of these beaded formulations can be found in U.S. Pat. Nos. 5,376,384, 5,529,790, 5,470,584, 5,002,776, 5,445,829 and 5,578,321. The product ORUVAIL.RTM. which is commercially available from Wyeth-Ayerst Laboratories, is another example of a controlled release pharmaceutical formulation that employs the bead technology. The ORUVAIL.RTM. product is available in 100 mg, 150 mg and 200 mg capsules and contains hundreds of coated pellets that consist of ketoprofen, ethylcellulose, gelatin, shellac, silicon dioxide, sodium lauryl sulfate, starch, sucrose, talc, titanium dioxide, dyes and other proprietary ingredients.
It is an object of the present invention to provide a controlled or sustained release dosage formulation for an analgesic that is easy to manufacture and can be used to prepare a range of dosing levels.
It is a further object of the present invention to provide a controlled or sustained release dosage formulation for an analgesic that can be prepared with only one coating layer.
It is an additional object of the present invention to provide a controlled or sustained release dosage formulation for an analgesic that can provide continuous and non-pulsating therapeutic levels of the analgesic to an animal or human in need of such treatment over a twelve hour to twenty-four hour period.